1. Field of the Invention
The present invention generally relates to security systems and, more particularly, to an exit door security system of an improved type.
2. Prior Art
Emergency exit doors must be provided by law in many buildings to permit such evacuation of building personnel in the event of a fire, earthquake or other emergency. Such exit doors generally have horizontal panic bars which permit them to be swiftly and easily opened from the inside and exited. Consequently, emergency exit doors are one means by which thieves can easily exit buildings, evading security personnel. Grocery stores, jewelry stores, clothing stores and the like suffer much loss from pilferage, with money thieves escaping through emergency exit doors. Some stores hire extra security personnel for stationing around emergency exits to reduce this risk, but such security personnel are expensive.
Other methods for solving the problem have been proposed, such as the system disclosed in U.S. Pat. No. 4,257,631 which issued on Mar. 24, 1981, to Emanuel Logan, Jr. This system is activated by a push bar which, upon depression, moves a switch carried by the door to sound an alarm and start the timer delay. Although a form of delayed opening of an emergency door is provided, the system depends upon actuation by movement of the push bar and does not sound an alarm if the door is opened without movement of the push bar (as by kicking the door to break bolt 14). Further, since the switch is carried by the door, power must be provided to the door, which is more complicated and less desirable than a fixed electrical system that perhaps is contained solely in the door jamb.
Accordingly, there is a need for an improved exit door security system which will be inexpensive, durable and effective in preventing exiting by thieves, but will not impede use of the exits in an emergency. It would also not have any requirement to deliver power to the door itself. Such system should reduce the need for security personnel, thereby effecting substantial savings for the stores, banks, etc. using such a system.